Method of electrolyzing salts



(No Model.)

T. CRANEY.

METHOD OF ELEGTROLYZING SALTS. No. 498,769. Patented June 6, 1893.

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UNITED STATES PATENT OFFICE.

THOMAS CRANEY, OF BAY CITY, MICHIGAN.

METHOD OF ELECTROLYZING SALTS.

SPECIFICATION forming part of Letters Patent No. 498,769, dated June 6, 1893.

Application filed August 10, 1892. Serial No. 442,648. (No specimens.)

To @ZZ whom it may concern:

Be it known that I, THOMAS ORANEY, aciti- ,zen of the United States, residing at Bay City,

' Vfor the electrolysis of salts in solution.

My invention consists in a novel method, whereby the desired product of electrolysis is obtained in ahigh state of concentration,and it further consists in an apparatus for carrying out such method.

In the following description I will describe and show my invention as applied to the manufacture of sodic hydrate from salt brine, and the apparatus which I have devised for the purpose of carrying out my method is specifically designed' for the commercial manufacture of such sodic hydrate in concentrated form, so that the product may be used commercially, as for instance in manufacturing soap.

In the accompanying drawings, Figure l shows a vertical central section of one of the electrolytic cells of which my apparatus is composed. Fig. 2 shows my apparatus in elevation. Fig. 3 is a plan view of Fig. 2.

My apparatus consists of a series of cellsA each containing two communicating compartments as shown in Fig. l, B representing the anode compartment, and B the cathode compartment of the cell, the two being formed preferably integral in one piece connected at the base througha hollow trunk C. The cell may be formed of stone or glassware or any other of the different materials found suitable for the purpose. Each of the chambers B B is preferably of cylindrical shape with an annular flange D around the top into which fits the cover E, which cover is suitably apertured to respectively receive an anode F and cathode G. The anodes and cathodes may be of any known construction; in the drawings the anode F consists of an open ended tube of glass or stoneware or other like indestructible material, and is filled or packed with carbon with which the terminal of the circuit is in electrical connection. The lower end of this tube projects into acup I-I, which is also filled with carbon exposed on the surface to contact with the solution to be electrolyzed. The cathode G to which the other terminal of the electric circuit is secured is shown as consisting of a sheet of metal loosely rolled so as to present a large surface in contact with the solution.

The two compartments B B are covered at the bottom to a suitable height above the trunk passage C, with an inert porous substance such as asbestus, sand, dac., or preferably with a body of the solid substance to be electrolyzed, which in the case of the decomposition of brine would be a body of common salt. Above this to a certain height the compartments are filled with the salt brine. Each compartment has inlet and outlet connections J, K, on opposite sides. The inlet connection J extends upwardly and the outlet connection K extends downwardly, and the two connections are adapted to forni a joint when the cells are arranged in a descending level as shown in Figs. 2 and 3. As each succeeding cell in the series is placed upon a lower plane than the preceding cell the level of the solution in the different cells is in like manner maintained in different horizontal planes gradually descending from the first cell to the last cell from which the product isdischarged.

The solution of the salt to be decomposed is fed either in a continuous stream or intermittently into the two compartments ofthe first cell, the drawings showing a feed pipe L, from which valve-controlled supply pipes M M pass into the compartments B B. From there the solution overflows from one compartment into the corresponding next one and so on through the series of cells, being discharged from the compartments of the last cell into separate receptacles O O.

In the manufacture of sodic hydrate the common salt brine as taken from the salt wells may be used, and this is decomposed by the electrolytic action of the current which is made to pass through all the cells by means of suitable feeders P P arranged in multiple between the main conductors Q Q of the generator. The product of decomposition is then sodic hydrate which is formed in the compart` ments B accompanied by the formation of IGO hydrogen gas, while chlorine gas is evolved in the compartments B. The chlorine gas in a measure will be carried olf in solution with the overflow into the receptacle O and may be recovered therefrom, if desired, forinstance, by heating the solution or it may be allowed to escape through suitable openings formed in the cover of the compartments B. The gaseous chlorine being heavier than atmospheric air will, if no other escape is provided, flow from one cell into the next and escape at the discharge of the last cell Where it may be separately connected. The hydrogen gas may also be allowed to escape from each compartment B separately through suitable openings or pipes or as it is lighter than atmospheric air it maybe allowed to rise into the highest compartment and from there allowed to escape.

In explaining myinvention let us now suppose an ample flow of the liquid to be electrolyzed to be taking place into the anode compartment of the first cell from which it overflows into the corresponding compartment of the next cell, and so on to the last cell, from which it is discharged. This will maintain in the different anode compartments through the whole series practically a saturatedv solution of the salt to be electrolyzed. The supply of solution into the cathode side ot' the apparatus is regulated according to the capacity of the apparatus to decompose'most or all the salt by the time it overilowed from the last compartment B of the series.

It will be seen that the amount of solution fed into the cathode side of the apparatus is subjected to decomposition in each compartwill increase from cell to cell, but the gradual concentration of the sodic hydrate will not arise only from this cause, but as the anode compartments contain practically a saturated lsolution of the salt maintained'by an abundant feed, the anode chambers will actively continue to transfer sodic hydrate into the cathode chamber, and thereby constantly add to the quantity of sodic hydrate. By this accumulative method of electrolyzing I have succeeded in obtaining sodic hydrate injany desired state of concentration by merely regulating the feed into the cathode chamber.

My method is altogether different from the ordinary process of subjecting a certain quantity of a solution of salt to electrolysis, as even if the decomposition of the salt shall be carried to its utmost possible limit (which is practically too expensive) the product would not be concentrated, while with my method l can produce sodic hydrate having the consistency of Sirup as regards concentration.

The solution of salt of the cathode side need not beconcentrated as even if water alone would` be introduced, the process would not be very materially altered as the liquid is mainly necessary to discharge the sodic hydrate from the apparatus. Up to a certain point however, the amount of sodic hydrate discharged from the apparatus is increased by feedinga solution of the salt into the cathode side of the apparatus, but if more is fed than can be decomposedthe final product of sodic hydrate would ot' course contain some of the undecomposed salt.

To obtain the product in a concentrated form it is necessary that the contents of each cathode chamber should be asm uch separated as possible from any other chamber, both for the purpose of preventing the reuniting of the different products as well as to prevent the sodic hydrate in one compartment from mixing with that in another compartment. The first object. is obtained by separating the compartments in each cell by a porous diaphragm, and the second is obtained by means of the different levels maintained by the solutions in the different cells. The arrangement by which this is carried out is also of great importance as it is about the only way in which a series of cells can be joined together. In my mode thejoint between two cells t is never submerged' by the liquid in the cell for if this were the case it would be practically impossible to prevent leakage, as sodic hydrate would attack and soon destroy any of the l known cements that could be used for a packi ing between the connections J and K.

With my construction there is no difficulty jfrom leakage and if desired gas tight, joints may be readily made and maintained by the use of cement. i

ment and thus the quantity of sodic hydrate from common salt, the solution going to waste -on the anode side by overflowing is not of :much account as it ordinarily costs merely In the case ot' manufacturing sodic hydrate the price of pumping, but if desired it can be freed from chlorine and used again.

What I claim as my invention is- The herein described method of electrolyzing salts in solution, the same consisting in subjecting the solution to electrolytic action in anode and cathode compartments sepa- .rated by an electrolytic diaphragm, in supplying during the operation fresh solution of the salt into the anode compartment in quantity to maintain the solution in concentra- Etion in supplyingthe cathode chamber with f a limited amount of the solution,and in regulating such supply to produce a discharge of i the product in a uniform state of concentral tion,substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

THOMAS CRANEY. Vitnesses:

N. L. LINDOP, JAMEs WHITTEMORE.

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